Which idea holds that all living things are composed of cells, and that cells are the basic units of structure and function, with new cells arising from existing cells?

Which idea holds that all living things are composed of cells, and that cells are the basic units of structure and function, with new cells arising from existing cells?

• A. Cell Theory
• B. Germ Theory
• C. Evolutionary Theory
• D. Molecular Theory

Answer: (A)

Cell theory is the statement that all living things are made of cells, that cells are the basic units of structure and function, and that new cells arise from existing cells. This ties together what life is built from, how organisms grow and maintain their structure, and how reproduction happens at the cellular level. Historically, scientists like Schleiden and Schwann showed that tissues and organisms are composed of cells, and Virchow added that every new cell comes from a pre-existing cell, which rules out the idea that cells can arise spontaneously. That combination—cellular composition, functional unit status, and reproduction by division—fits the prompt perfectly. The other options describe different ideas: Germ Theory explains disease-causing microbes, Evolutionary Theory explains how life diversifies over time, and Molecular Theory focuses on the chemical components and interactions within living systems, not the cellular basis of life or how cells reproduce.

Cell theory is the statement that all living things are made of cells, that cells are the basic units of structure and function, and that new cells arise from existing cells. This ties together what life is built from, how organisms grow and maintain their structure, and how reproduction happens at the cellular level. Historically, scientists like Schleiden and Schwann showed that tissues and organisms are composed of cells, and Virchow added that every new cell comes from a pre-existing cell, which rules out the idea that cells can arise spontaneously. That combination—cellular composition, functional unit status, and reproduction by division—fits the prompt perfectly. The other options describe different ideas: Germ Theory explains disease-causing microbes, Evolutionary Theory explains how life diversifies over time, and Molecular Theory focuses on the chemical components and interactions within living systems, not the cellular basis of life or how cells reproduce.